JPH0327760Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention mainly relates to an elevating device for a movable platen in a glass fiber reinforced plastic (FRP) forming press.

Conventionally, in this type of forming press, as shown in FIG. The movable board 3 is configured to slide up and down along a pair of side frames 5 supporting the board 1, and an upper die 6 attached to the lower surface of the movable board 3 is attached to a mounting member 7 on the lower board 4. The upper and lower molds 6, 8 are pressed and pressurized by the lower mold 8 attached through the
It is known that the product is molded in the cavity between the two.

By the way, in the molding process of the molded product in the molding press configured as above, the movable platen 3
Depending on the position, no-load high-speed descending process, machining process,
It is roughly divided into a mold release process and a high-speed raising process, and among these, the processing process and mold release process are performed by driving a large main cylinder capable of applying high pressure. The no-load high-speed descending process uses the self-weight fall of the movable platen 3 or an auxiliary cylinder for high speed, and the high-speed ascending process uses a differential circuit or an auxiliary cylinder to pull up or push it up as in the high-speed descending process. There is.

When the movable platen 3 is raised at high speed, either the differential circuit or the auxiliary cylinder is used to raise the movable platen 3 and the upper die 6 attached to the movable platen 3 against its weight. In order to achieve this, a considerable amount of pressure oil must be rapidly supplied, and the capacity of the pump and its drive device must be increased. (pressurization + demolding + high-speed rise) is a short period of several seconds, and installing a large-capacity pump and its drive device as mentioned above just for that purpose is extremely wasteful.
The problem is that it is not efficient.

This invention solves the above conventional problems,
The object is to provide a lifting device for a movable platen in a forming press that has a simple structure and allows for efficient operation and equipment utilization with less waste.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Reference numeral 10 in FIG. 2 is a movable platen of a conventionally known molding press, and on the upper surface of this movable platen 10 are provided the tips of the piston rods 13 and 14 of the two main cylinders 11 and 12 and the tip of the piston rod 16 of the auxiliary cylinder 15. are connected. The upper end of each main cylinder 11, 12 is connected to a semi-closed type servo pump (first pump) 17 that can change the amount of oil discharged and the direction of oil flow through piping.
A pair of prefill valves 1 which are connected to ○A at one end and are opened by a command from a pilot line P1.
8, 19 and the oil tank via the relief valve 20.
Connected to OT. The two check valves 21 and 22 of the servo pump 17 are connected to the oil tank through the ○ and ○ ends.
Connected to OT. In addition, the servo pump 17
The other end ○C is connected to the lower end of the auxiliary cylinder 15 via one end of the first switching valve 23, one end of the third switching valve (bleed-off device) 24, one end of the check valve 25, and the counterbalance valve CB. connected. The other end of the first switching valve 23 is connected to each main cylinder 1.
1 and 12, and is also connected to the oil tank OT via a pair of prefill valves 26 and 27, which are opened by a command from the pilot line P2. As is well known, the pilot lines P1 and P2 are each connected to a pilot pump (not shown) via an electromagnetic switching valve (not shown), and when the control device X gives a command to the electromagnetic switching valve, , the prefill valves 18 and 19 or the prefill valves 26 and 27 are opened and closed. Further, the other end of the third switching valve 24 is connected to the oil tank OT via a variable first flow rate regulating valve 28. In addition, the check valve 25
The other end sequentially includes a variable second flow rate regulating valve 29,
Second switching valve 30, accumulator 31, check valve 3
2 to a small-capacity high-pressure pump unit (second pump) 33. This small-capacity high-pressure pump unit 33 has a capacity sufficient to store a sufficient amount of pressure oil in the accumulator 31 to raise the movable platen 10 at high speed during the molding cycle excluding the high-speed raising step. It would be good if there was
It is designed to be driven by a command from the control device X.

The rack 34 provided on the movable platen 10 includes
A pinion 36 attached to the rotating shaft 35a of a position detecting device 35 such as an absolute rotary encoder and a pinion 38 having a smaller diameter than the pinion 36 attached to the rotating shaft 37a of a speed detecting device 37 such as an incremental rotary encoder are meshed with each other. There is. The position detection device 35 and speed detection device 37 are electrically connected to the control device It is designed to be compared with pre-input setting values (position, speed). Then, based on the results of this comparison, the control device
commands the discharge direction and discharge oil amount to the servo pump 17, and the first, second, third
A command is given to the switching valves 23, 24, 30 and the solenoid valve SV of the counterbalance valve CB, and each valve 2
It is designed to switch between 3, 24, 30, and SV.

Next, the operation of the elevating device for the movable platen in the molding press according to the present invention will be explained.

The movable platen 10 is in the uppermost position (mold open state)
, and with the first, second, and third switching valves 23, 24, and 30 closed, the control device X gives a command to the pilot lines P1 and P2 to open each prefill valve 18, 19, 26, and 27. Then, the piston rods 13 and 14 of each main cylinder 11 and 12 are set in a free state, and the control device X gives a command to the solenoid valve SV of the counterbalance valve CB and the third switching valve 24, and the When the unloaded state is set and the third switching valve 24 is opened, the pressure oil in the auxiliary cylinder 15 is transferred to the counterbalance valve.
It flows into the oil tank OT through the CB, the third switching valve 24, and the first flow rate adjustment valve 28, and flows into the auxiliary cylinder 1.
The movable platen 10 connected to the piston rod 16 of No. 5 starts to descend at high speed due to its own weight. Then, when the movable platen 10, which is descending at a speed determined by the first flow rate regulating valve 28, reaches a predetermined position, the output of the position detection device 35 is input to the control device X. , the control device
Close the solenoid valve SV of CB and open the counterbalance valve.
With CB on-load, servo pump 17
As a result, pressure oil is supplied to the upper end side of each main cylinder 11, 12. When pressurized oil is supplied to the upper ends of the main cylinders 11, 12, the movable platen 10 connected to the piston rods 13, 14, 16 of each cylinder 11, 12, 15 will not fall due to its own weight, According to the amount of pressurized oil supplied to the upper ends of the main cylinders 11 and 12, the piston rods 13, 14, and 16 descend at low speed in conjunction with the descending movement of each piston rod 13, 14, 16 while applying back pressure by the counterbalance valve CB. As a result, the upper mold attached to the movable platen 10 is brought together with the lower mold on the fixed side, and the molding material in the cavity formed by both molds is compression-molded.

In this way, after the pressurization process is completed and a molded product is formed in the mold cavity, the control device X gives a command to close each prefill valve 26, 27,
At the same time, the first switching valve 23 is opened, and the servo pump 17 is caused to discharge from the direction opposite to that during the pressurization process, thereby supplying pressure oil to the lower end sides of each of the main cylinders 11, 12 and the auxiliary cylinder 15. Apply pressure oil to each cylinder 11,
When supplied to the lower end side of cylinders 12 and 15, each cylinder 1
1, 12, 15 piston rods 13, 14, 1
A movable platen 10 connected to the piston rod 6 controls the upward movement of each piston rod 13, 14, 16 according to the amount of pressure oil supplied to the lower end side of each cylinder 11, 12, 15 according to a command from the control device X. The upper mold attached to the movable platen 10 separates from the lower mold by moving up at a low speed in conjunction with each other (mold release process). In this way, the upper mold is separated from the lower mold at a low speed, so
It is possible to prevent defects such as peeling, bending, and curling from occurring in the molded product formed between the upper mold and the lower mold.

When this mold release process is completed, the control device , the piston rods 13 and 14 of each main cylinder 11 and 12 are set free, and the second switching valve 30 is opened. At this time, since a sufficient amount of pressure oil is stored in advance in the accumulator 31 from the small-capacity high-pressure pump unit 33, the pressure oil in the accumulator 31 is transferred to the second flow rate regulating valve 29, the check valve 25, and the counter. It is rapidly supplied to the lower end side of the auxiliary cylinder 15 via the balance valve CB. Therefore, the movable platen 10 connected to the piston rod 16 of the auxiliary cylinder 15 moves up at high speed in conjunction with the upward movement of the piston rod 16 until it reaches a predetermined upper limit position. When the movable platen 10, which is rising at a speed determined by the second flow rate regulating valve 29, reaches the upper limit position, the control device X detects this arrival based on the output of the position detection device 35, and Accordingly, the control device Start storing oil. In this way, one molding cycle is completed.

In this embodiment, the small capacity high pressure pump unit 33
Therefore, the movable platen 10 is raised at high speed by supplying high-pressure oil from the accumulator 31 storing pressure oil to the auxiliary cylinder 15 between the end of one high-speed raising process and the start of the next high-speed raising process. Compared to the case where a large-capacity pump and its drive device were provided only for the high-speed rising step (several seconds) of a several-minute molding cycle, only an accumulator 31 and a small-capacity high-pressure pump unit 33 are provided. Therefore, the movable platen can be smoothly raised at high speed, and it has the effect of allowing extremely efficient operation and equipment utilization with no waste.

Furthermore, in this embodiment, the pressure oil in the auxiliary cylinder 15 is bled off to the oil tank OT via the third switching valve 24 and the first flow rate adjustment valve 28, so that the movable platen 10 can be lowered at high speed. By removing the pressure oil in the auxiliary cylinder 15, the movable platen 10 can be lowered rapidly.

As described above, this embodiment has excellent effects in that the movable platen 10 can be moved up and down at high speed, the molding cycle can be shortened, and product production efficiency can be improved.

It goes without saying that the equipment and hydraulic circuit configurations shown in this embodiment are basic and are not limited thereto.

As explained above, the main cylinder is connected to the first pump via the first switching valve, the auxiliary cylinder is connected to the accumulator via the second switching valve,
A second pump for storing pressure oil is connected to the accumulator, and opens the first switching valve at the beginning of the rise of the movable platen, and closes the first switching valve when the movable platen rises by a predetermined amount. At the same time, a control device is provided to open the second switching valve.
At the beginning of the movable platen's rise, the movable platen is raised at a low speed and the mold release process is performed at a low speed to prevent defects such as peeling, bending, and curling of the molded product. After the mold release process is completed, the pressure oil from the accumulator is supplied to the auxiliary cylinder to rapidly raise the movable platen, which has the effect of shortening the molding cycle.

[Brief explanation of the drawing]

Figure 1 is a schematic front view showing a conventional forming press;
FIG. 2 is a hydraulic circuit diagram showing an embodiment of the present invention. 10...Movable plate, 11, 12...Main cylinder,
15... Auxiliary cylinder, 17... Servo pump (first pump), 23... First switching valve, 30... Second switching valve, 31... Accumulator, 33... Small capacity high pressure pump (second pump) , X...control device.

Claims (1)

[Scope of utility model registration request] In a lifting device for a movable platen in a forming press having a main cylinder for pressurization and an auxiliary cylinder for moving the movable platen at high speed, the main cylinder is connected to a first pump via a first switching valve, and the auxiliary cylinder is connected to a first pump via a first switching valve. It is connected to the accumulator via a two-way switching valve, and the accumulator has a second valve that stores pressure oil.
When a pump is connected, the first switching valve is opened at the beginning of the rise of the movable platen, and when the movable platen has risen by a predetermined amount, the first switching valve is closed and the second switching valve is opened. An elevating device for a movable platen in a forming press, characterized in that it is equipped with a control device.